Vincristine (ex. Oncovan) and cyclophosphamide (ex. Cytoxan) are occasionally prescribed to treat ITP. These are second or third line treatments. Vincristine may be used in emergenices or in combination with other therapies for particularly difficult cases.6
Vincristine is a vinca alkaloid derived from the Madagascar periwinkle that inhibits the division of rapidly growing cells. It is frequently used in conjunction with other drugs or infusions for the treatment of lymphoma.1
Cyclophosphamide slows cell growth as well as suppresses the immune system. Most often used to treat lymphoma or other cancers, it alters T-cells2, a type of white blood cell, and may be preferentially considered for those ITP patients who have T-cell abnormalities.3
Rituximab (rituxan) is considered by some to be a chemotherapy since it is often used to treat cancer. Information about rituximab and ITP is on the B-cell depletion page.
The dose and duration of the chemotherapy agents varies with the age and size of the patient, other medications, and additional medical conditions.
Vincristine is administered through an IV push. It is important that someone who is experienced with the treatment oversee the process since leakage into the surrounding tissue can cause severe problems or death.4
Cyclophosphomide can be given by tablet or injection.5
Chemotherapy agents can reduce the number of white blood cells and increase the chance of getting an infection. The side effects become more severe with increased or additional doses.
The most frequently reported side effects of vincristine are peripheral neuropathy (reduced sensation in fingers and toes), electrolyte imbalance, constipation, and hair loss.1
Cyclophosphomide side effects include chemotherapy-induced nausea and vomiting, stomach ache, diarrhea, and infertility. Delayed effects include the risk of developing bladder cancer or other tumors.2,5
1. Wikipedia:vincristine http://en.wikipedia.org/wiki/Vincristine
2. Wikipedia: cyclophosphamide http://en.wikipedia.org/wiki/Cyclophosphamide
3. Sabnani I, Tsang P. “Therapeutic implications of T-cell clonopathy of unknown significance in chronic immune thrombocytopenic purpura.” Platelets. 2009 Mar;20(2):135-9. http://www.ncbi.nlm.nih.gov/pubmed/19235057
4. Vincristine package insert http://patient.cancerconsultants.com/druginserts/Vincristine.pdf
5. Cyclophosphamide package insert http://patient.cancerconsultants.com/druginserts/Cyclophosphamide.pdf
6. Provan, D, “International consensus report on the investigation and management of primary immune thrombocytopenia,” Blood. 2010 Jan 14; 115 (2):168-86.http://bloodjournal.hematologylibrary.org/cgi/content/full/115/2/168